Influence of rapid palatal expansion on maxillary incisor alignment stability

Introduction: The purpose of this retrospective study was to compare the long-term stability of maxillary incisor alignment in patients treated with and without rapid maxillary expansion (RME). Methods: The sample comprised 48 subjects with Class I and Class II malocclusions, treated without extractions with fixed edgewise appliances, divided into 2 groups according to the treatment protocol: group 1 comprised 25 patients (15 girls, 10 boys) at a mean initial age of 13.53 years (SD, 1.63), who had RME during orthodontic treatment. Group 2 comprised 23 patients (13 girls, 10 boys) at a mean initial age of 13.36 years (SD, 1.81 years), treated with fixed appliances without RME. Maxillary dental cast measurements were obtained at the pretreatment, posttreatment, and long-term posttreatment stages. Variables assessed were the irregularity index and maxillary arch dimensions. Intergroup comparisons were made with independent t tests. Results: Greater transverse increases were found during treatment in the group treated with RME. However, during the long-term posttreatment period, no significant difference was observed in the amount of incisor crowding relapse between the groups. Conclusions: RME did not influence long-term maxillary anterior alignment stability. (Am J Orthod Dentofacial Orthop 2010; 137: 164. e1-164.e6)

A Randomized Clinical Evaluation of a One- and Two-step Self-etch Adhesive Over 24 Months

Objective: To evaluate the performance of All Bond SE used in a one- or two-step protocol in a 24-month randomized clinical study. Methods: Thirty-three patients with two similarly sized non-carious cervical lesions participated in this study. A total of 66 restorations were placed, half using the one-step All Bond SE protocol (SE-1) and the other half using the two-step All Bond SE protocol (SE-2). The restorations were evaluated at baseline and after 6, 12 and 24 months following the modified USPHS criteria and analyzed by the McNemar`s test and Fisher`s exact test (alpha=0.05). Results: After 24 months, six SE-1 and four SE-2 restorations were rated as Bravo in marginal discoloration The retention rates for SE-1 and SE-2 were 84.8% and 90.9%, respectively, after 24 months. Compared to baseline, the retention rate for SE-1 was statistically lower. Conclusions: All Bond SE used in the one- or two-step protocol resulted in high retention rates after 24 months.

Strong Grobner bases for polynomials over a principal ideal ring

Grobner bases have been generalised to polynomials over a commutative ring A in several ways. Here we focus on strong Grobner bases, also known as D-bases. Several authors have shown that strong Grobner bases can be effectively constructed over a principal ideal domain. We show that this extends to any principal ideal ring. We characterise Grobner bases and strong Grobner bases when A is a principal ideal ring. We also give algorithms for computing Grobner bases and strong Grobner bases which generalise known algorithms to principal ideal rings. In particular, we give an algorithm for computing a strong Grobner basis over a finite-chain ring, for example a Galois ring.

Effects of Orthopedic Rapid Maxillary Expansion on Internal Nasal Dimensions in Children With Cleft Lip and Palate Assessed by Acoustic Rhinometry

The objective of the current study was to characterize the internal nasal dimensions of children with repaired cleft lip and palate and transverse maxillary deficiency, using acoustic rhinometry and analyze the changes caused by rapid maxillary expansion (RME). A convenience sampling of 19 cleft lip and palate individuals, aged 14 to 18 years, of both sexes, previously submitted to primary surgeries and referred for RME were analyzed prospectively at the Hospital for Rehabilitation of Craniofacial Anomalies, University of Sao Paulo, Bauru, Sao Paulo, Brazil. All patients underwent acoustic rhinometry before installation of the expansor and at 30 and 180 days after the active expansion phase. Nasal cross-sectional areas and volumes corresponding to the nasal valve (CSA(1) and V(1)) and the turbinates (CSA(2), CSA(3), and V(2)) regions were determined before and after nasal decongestion. Rapid maxillary expansion led to a statistically significant increase (P < 0.05) in mean CSA(1), CSA(2), V(1), and V(2) (without nasal decongestion) and in CSA(1) and V(1) (with decongestion) in the group as a whole. Individual data analysis showed that 58% of the patients responded positively to RME, with an average increase in CSA(1) of 26% (with decongestion), whereas 37% of the patients had no significant change. Only 1 patient (5%) showed a decrease. The findings contribute toward the characterization of nasal deformities determined by the cleft and demonstrate the positive effect RME had on nasal morphophysiology in a significant number of the patients who underwent this procedure.

Rapid maxillary expansion causes neuronal activation in brain structures of rats

A correlation between pain sensation and neuronal c-fos expression has been analyzed following experimental rapid maxillar expansion (RME). Adult male Wistar rats were anaesthetized and divided into three groups: animals that received an orthodontic apparatus, which was immediately removed after the insertion (control), animals that received an inactivated orthodontic apparatus (without force), and animals that received an orthodontic apparatus previously activated (140 g force). After 6, 24, 48, or 72 h, the animals were re-anaesthetized, and perfused with 4% paraformaldehyde. The brains were removed, fixed, and sections containing brain structures related to nociception were processed for Fos protein immunohistochemistry (IHC). The insertion of the orthodontic apparatus with 140 g was able to cause RME that could be seen by radiography. The IHC results showed that the number of activated neurons in the different nuclei changed according to the duration of appliance insertion and followed a temporal pattern similar to that of sensations described in clinics. The animals that received the orthodontic apparatus without force did not show RME but a smaller c-fos expression in the same brain structures. In conclusion, we demonstrate that orthodontic force used for palate disjunction activates brain structures that are related to nociception, and that this activation is related to the pain sensation described during orthodontic treatment. (c) 2008 Elsevier Inc. All rights reserved.

Matrix-product codes over Fq

Codes C-1,...,C-M of length it over F-q and an M x N matrix A over F-q define a matrix-product code C = [C-1 (...) C-M] (.) A consisting of all matrix products [c(1) (...) c(M)] (.) A. This generalizes the (u/u + v)-, (u + v + w/2u + v/u)-, (a + x/b + x/a + b + x)-, (u + v/u - v)- etc. constructions. We study matrix-product codes using Linear Algebra. This provides a basis for a unified analysis of /C/, d(C), the minimum Hamming distance of C, and C-perpendicular to. It also reveals an interesting connection with MDS codes. We determine /C/ when A is non-singular. To underbound d(C), we need A to be 'non-singular by columns (NSC)'. We investigate NSC matrices. We show that Generalized Reed-Muller codes are iterative NSC matrix-product codes, generalizing the construction of Reed-Muller codes, as are the ternary 'Main Sequence codes'. We obtain a simpler proof of the minimum Hamming distance of such families of codes. If A is square and NSC, C-perpendicular to can be described using C-1(perpendicular to),...,C-M(perpendicular to) and a transformation of A. This yields d(C-perpendicular to). Finally we show that an NSC matrix-product code is a generalized concatenated code.

An evaluation of the changes in malocclusion index scores over a 25-year period

Background: The measured values of specific traits of occlusion may be subject to significant change due to growth and maturation of the dentofacial structures. Some traits may show improvement while others may show deterioration. Rarely is there an opportunity to examine a sample of occlusions 25 years after the acquisition of the original set of records. This study examines the changes in traits of occlusion in a sample of 46 subjects who were originally examined between 1971-1973 and for whom records were again obtained in 1998. Methods: The 46 patients were a sub-group of a previously selected randomised school-based sample and study models obtained in 1971-1973 were still available. New models for each patient were obtained in 1998. Of the 46 subjects, only eight had received orthodontic treatment. Results: Assessments of the changes in specific traits were made using the methods proposed in the Harry L Draker, California Modification (HLD Cal Mod) index. This simple index was chosen because the main component traits were well defined and, when analysed separately, reflected changes with time. The total index score gave a broad indication of the global changes in the individual's occlusion. The five basic traits of the HLD index include overjet, overbite, openbite, mandibular protrusion and labio-lingual spread. Three additional traits (ectopic eruption, anterior crowding and posterior crossbite) are used in the HLD Cal Mod index. These traits provided a useful reflection of occlusal changes with time. Measurements were made with reference to specifications and the details outlined in the HLD Cal Mod protocol. The results revealed an increase in total index scores over time with a significant increase in lower labio-lingual spread associated with an increased score in anterior crowding. Overjet and overbite, however, displayed a significant decrease with time. Conclusions: These findings are in keeping with previous studies and highlight the importance of time as a significant issue in the assessment of occlusion.

Geographic variation of notified Ross River virus infections in Queensland, Australia, 1985-1996

The spatial and temporal variations of Ross River virus infections reported in Queensland, Australia, between 1985 and 1996 were studied by using the Geographic Information System. The notified cases of Ross River virus infection came from 489 localities between 1985 and 1988, 805 between 1989 and 1992, and 1,157 between 1993 and 1996 (X (2)((df = 2)) = 680.9; P < 0.001). There was a marked increase in the number of localities where the cases were reported by 65 percent for the period of 1989-1992 and 137 percent for 1993-1996, compared with that for 1985-1988. The geographic distribution of the notified Ross River virus cases has expanded in Queensland over recent years. As Ross River virus disease has impacted considerably on tourism and industry, as well as on residents of affected areas, more research is required to explore the causes of the geographic expansion of the notified Ross River virus infections.

Subspace wavepacket evolution with Newton polynomials

Time-dependent wavepacket evolution techniques demand the action of the propagator, exp(-iHt/(h)over-bar), on a suitable initial wavepacket. When a complex absorbing potential is added to the Hamiltonian for combating unwanted reflection effects, polynomial expansions of the propagator are selected on their ability to cope with non-Hermiticity. An efficient subspace implementation of the Newton polynomial expansion scheme that requires fewer dense matrix-vector multiplications than its grid-based counterpart has been devised. Performance improvements are illustrated with some benchmark one and two-dimensional examples. (C) 2001 Elsevier Science B.V. All rights reserved.

The measurement of Pitot pressure in high enthalpy expansion tubes

Expansion tubes operating at total flow enthalpies of 100 MJ kg(-1) or more have characteristical test times of 30-50 mus. Under these conditions, the response time of the Pitot pressure measuring device is critical when performing flow calibration studies. The conventional technique of using a commercial pressure transducer protected by shielding has not always proven to be effective, due to the relatively large (and variable) response time caused by the shielding. A device called the stress wave bar gauge has been designed and calibrated and shown to be an effective way to measure the Pitot pressure with a response time of only 2-3 mus.

Family dynasties in the Tasmanian native hen (Gallinula mortierii)

For species that form multi-generational and territorial family groups, resource-rich areas are predicted to support family dynasties in which one genetic lineage continuously occupies an area and may even expand to occupy surrounding areas. Data from a long-term study of Tasmanian native hens (Gallinula mortierii) support this prediction. The reproductive success and dispersal patterns of 18 hen lineages were monitored for seven breeding seasons and over several generations. The founder group with the highest average territory quality produced the highest total number of fledged young and the highest number of fledged linear descendants, accounting for 24% of the combined reproductive output of these 18 lineages. In the space of 6 years, this single genetic lineage expanded from one territory to occupy 12 of the 47 territories present in the population. This rate of expansion was over four times the population average for the same period. A multivariate analysis revealed that the success of a genetic lineage depended only on the number of high-quality territories surrounding the founder group. These results further demonstrate the resource-dependent nature of reproductive success in this species, and also highlight the potential importance of family dynasties in other cooperative species with complex social dynamics and dispersal patterns.

Breaking the deadlock over an Australian trial of injectable opioid maintenance

INJECTABLE HEROIN MAINTENANCE has been advocated as a form of treatment for opioid dependence that would attract, and retain in treatment, addicts who have either not sought treatment or who have failed at other forms of treatment, including methadone maintenance. Advocates of heroin maintenance argue that it would increase the proportion of addicts in treatment and reduce heroin use, drug related crime, and deaths due to overdose.